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0011112 I I I I I I I I I I I I I I I I I I I b. A chute opened up in Bend No. 4 but the concave bank moved very 1 ittle. c. Bend No.8 moved downstream two-thirds of a channel width. d. The remaining 10 bends were essentially unchanged in this 7 year period. The conclusion is that the largest flood in the period of record did not cause appreciable movement of the river in the study reach. 9. Vertical Stability The records of the di scharge measurements taken in Cherry Creek near Melvin were examined to determine whether the streambed is aggrading, de- grading, or remaining fixed with respect to time. The rating curves prepared by the USGS from the measurements are shown in Figure-5. Prior to the 1st of October, 1960, the streamgage was located at a site one mile downstream from Arapahoe Road. The gage datum (elevation of the zero point on the water level gage) was 5608.21 feet above mean sea level. Accor- ding to the rating curves, the zero flow level at this site varied from eleva- tion 5608.7 to 5610.4 feet; that is. the bend could have changed approxi- mately 1.7 feet in elevation. These changes did not correlate with the annual streamflow or with peak floods. From October, 1960 to June, 1965, the zero flow level for the site on the right bank on the downstream side of Arapahoe Road was at elevation 5628.5 feet above mean sea level. The flood of June, 1965 degraded the bed of Cherry Creek downstream from Arapahoe Road so that the zero flow level dropped 2.7 feet to elevation 5625.8. Thereafter, the bed aggraded approximately 0.3 feet to ele- vation 5626.1 feet and remained that way until the gage was discontinued in 1969. In 1983, the bed level at the bridge was elevation 5631.0 feet indicating that since 1964, the streambed had risen 2.5 feet and since 1965, 4.9 feet. -20-